1. Field of Invention
The invention relates to apparatus and methods for applying wax or another substance to the surfaces of objects, and more particularly to the application of wax to citrus fruit on a conveyor system.
2. Description of the Prior Art
It is a well established procedure in the processing and sorting of fruit, and, in particular citrus fruit, to finish the fruit by applying a protective, preservative and cosmetically enhancing surface layer of wax or other material. Typically, the wax is applied to objects, or specifically to fruit, in a conveyor line by spraying a liquid wax onto the fruit as it is rotated on a brush bed conveyor and advanced to a packaging station.
However, applying the appropriate amount of wax to each run of fruit is often difficult to control if optimal results and efficient use of the wax is to be achieved. The optimum amount of wax varies according to the fruit size and variety of fruit to which the wax is applied, and also, to some extent, varies seasonally. The wax volume which must be sprayed onto the fruit also varies according to the speed of the fruit through the waxer. The efficiency of the wax application varies according to the distribution of fruit on the conveyor bed in the waxer and in particular with respect to the lateral distribution of the fruit as it travels underneath the spray nozzles. Further non-uniformity of wax application is experienced when the conveyor line, for any number of reasons, may be stopped.
The amount of wax which must be applied to the fruit varies according to the type of wax which is used. Fruit in the center of the waxer tends to move through the waxer faster than fruit on the sides, which also results in an uneven wax application. Changing the wax nozzles to accommodate this type of variation is often impractical. The droplet size distribution of the wax sprayed onto the fruit for a given nozzle is typically constant and it is difficult to vary the amount of wax applied to the fruit without changing nozzles. Still further, the quality and nature of the wax application will vary with the amount of brush wear in the underlying brush bed and also whether the brush bed was pre-loaded with wax prior to the fruit flow. Finally, the quality of the resulting wax application still further varies with the skin texture of the fruit.
All of these variables with respect to applying the wax to the fruit make it extremely difficult to obtain an efficient use of the wax and/or a high shine, uniform fruit pack-out. Therefore, what is needed is some type of apparatus and method in which each of these variables may be adjusted in order to provide both cost effective and efficient wax usage, high uniform wax applications and hence uniform shine in the fruit pack-out.